Hi can someone please help me

1. Determine the speed at which a satellite must be moving in order to maintain a low orbit 151 km above the Earth where the gravitational field strength is 9.38 N/kg. Then calculate its orbital period. (6 marks) 2. Mars has two moons, Phobos and Deimos. Deimos has a period of 30 h 18 min and a mean distance from the centre of Mars of 2.3 x 10* km. If the period of Phobos is 7 h 39 min, what mean distance is it from the centre of Mars? (3 marks) 3. What is the escape velocity for Mercury (mass 3.35 x 1023kg; radius 2.44 x 10m; g = 3.7 m/s?)